I don't wash the berries because you want them to be completely dry, and they don't get dirty on the bushes. You can throw out any that concern you when you pick them over. Remove all the little gray stems, and any debris from your collection efforts. This is the tedious part. Discard any berries that are shriveled or hard. Your goal is berries that will be eaten raw.

autumn olive berries ready for the first freezing (photo by jhy)

Place berries on a cookie sheet or other metal tray with a lip, in one layer. Don't spread them more than one layer deep. Put the tray of berries in the freezer, uncovered for about a day. This will freeze the berries solid, but they will still be loose, not clumped together or squashed.

frozen packet of autumn olive berries (photo by jhy)

Remove berries from the tray and double bag. Label and return to the freezer. The berries pictured in the bag are what is left of the ones I froze last year, and they are still loose and perfectly good to use.

I like to use these as a garnish on yogurt or salad. I think the flavor is particularly nice on salad and the slight crunch of the seeds is masked by the crunch of the salad. I just open the bags and take out what I want, then press the air out of the bags, reseal and place it back in the freezer.